MAP Kinase Phosphatase-5 Deficiency Protects Against Pressure Overload-Induced Cardiac Fibrosis

Cardiac fibrosis, a pathological condition due to excessive extracellular matrix (ECM) deposition in the myocardium, is associated with nearly all forms of heart disease. The processes and mechanisms that regulate cardiac fibrosis are not fully understood. In response to cardiac injury, macrophages undergo marked phenotypic and functional changes and act as crucial regulators of myocardial fibrotic remodeling. Here we show that the mitogen-activated protein kinase (MAPK) phosphatase-5 (MKP-5) in macrophages is involved in pressure overload-induced cardiac fibrosis. Cardiac pressure overload resulting from transverse aortic constriction (TAC) leads to the upregulation of Mkp-5 gene expression in the heart. In mice lacking MKP-5, p38 MAPK and JNK were hyperactivated in the heart, and TAC-induced cardiac hypertrophy and myocardial fibrosis were attenuated. MKP-5 deficiency upregulated the expression of the ECM-degrading matrix metalloproteinase-9 (Mmp-9) in the Ly6C^low (M2-type) cardiac macrophage subset. Consistent with in vivo findings, MKP-5 deficiency promoted MMP-9 expression and activity of pro-fibrotic macrophages in response to IL-4 stimulation. Furthermore, using pharmacological inhibitors against p38 MAPK, JNK, and ERK, we demonstrated that MKP-5 suppresses MMP-9 expression through a combined effect of p38 MAPK/JNK/ERK, which subsequently contributes to the inhibition of ECM-degrading activity. Taken together, our study indicates that pressure overload induces MKP-5 expression and facilitates cardiac hypertrophy and fibrosis. MKP-5 deficiency attenuates cardiac fibrosis through MAPK-mediated regulation of MMP-9 expression in Ly6C^low cardiac macrophages.

The Fractalkine Receptor CX3CR1 Links Lymphocyte Kinetics in CMV-Seropositive Patients and Acute Myocardial Infarction With Adverse Left Ventricular Remodeling

Aims

Latent cytomegalovirus (CMV) infection is associated with adverse cardiovascular outcomes. Virus-specific CX3CR1+ effector memory T-cells may be instrumental in this process due to their pro-inflammatory properties. We investigated the role of CX3CR1 (fractalkine receptor) in CMV-related lymphocyte kinetics and cardiac remodeling in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI).

Methods and Results

We retrospectively analysed lymphocyte count, troponin, and survival in 4874 STEMI/pPCI patients, evaluated lymphocyte kinetics during reperfusion in a prospective cohort, and obtained sequential cardiac MRI (cMRI) to assess remodeling. Pre-reperfusion lymphopenia independently predicted mortality at 7.5 years. Prior to reperfusion, CCR7+ T-lymphocytes appeared to be depleted. After reperfusion, T-lymphocytes expressing CX3CR1 were depleted predominantly in CMV-seropositive patients. During ischaemia/reperfusion, a drop in CX3CR1+ T-lymphocytes was significantly linked with microvascular obstruction in CMV+ patients, suggesting increased fractalkine-receptor interaction. At 12 weeks, CMV+ patients displayed adverse LV remodeling.

Conclusion

We show that lymphopenia occurs before and after reperfusion in STEMI by different mechanisms and predicts long-term outcome. In CMV+ patients, increased fractalkine induction and sequestration of CX3CR1+ T-cells may contribute to adverse remodeling, suggesting a pro-inflammatory pathomechanism which presents a novel therapeutic target.

Critical roles of macrophages in pressure overload-induced cardiac remodeling

Macrophages are integral components of the mammalian heart that show extensive expansion in response to various internal or external stimuli. After the onset of sustained pressure overload (PO), the accumulation of cardiac macrophages through local macrophage proliferation and monocyte migration has profound effects on the transition to cardiac hypertrophy and remodeling. In this review, we describe the heterogeneity and diversity of cardiac macrophages and summarize the current understanding of the important roles of macrophages in PO-induced cardiac remodeling. In addition, the possible mechanisms involved in macrophage modulation are also described. Finally, considering the significant effects of cardiac macrophages, we highlight their emerging role as therapeutic targets for alleviating pathological cardiac remodeling after PO.

RETRACTED: Bone marrow mesenchymal stem cells-derived exosomal microRNA-185 represses ventricular remolding of mice with myocardial infarction by inhibiting SOCS2

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the integrity of the images in Figures 5B and 7C, which appear to contain suspected duplications, as detailed here: https://pubpeer.com/publications/C968FDCECE2069D7FF43B346B261ED and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Numerous additional suspected image duplications were detected within Figures 5 and 6. Most of these image duplications involve either pasting portions of one image into another, or rotating/flipping the image. The journal requested the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Inhibition of peptidyl arginine deiminase-4 protects against myocardial infarction induced cardiac dysfunction

Peptidyl arginine deiminase-4 (PAD4), a PAD enzyme family member, catalyzes the posttranslational conversion of arginine residues to citrulline in target proteins. Although PAD4 is believed to play a crucial role in various pathological conditions such as infectious diseases, autoimmune diseases, and ischemic conditions, the effect of PAD4 in myocardial infarction (MI)-induced cardiac injury remains to be examined. Here, we hypothesize that PAD4 contributes to cardiac ischemic injury by exacerbating the inflammatory response and promoting neutrophil extracellular trap (NET) formation after MI. Permanent left coronary artery ligation, a condition that mimics MI, was performed on male C57BL/6 mice. [(3S,4R)-3-amino-4-hydroxy-1-piperidinyl] [2-[1-(cyclopropylmethyl)-1H-indol-2-yl]-7-methoxy-1-methyl-1H-benzimidazol-5-yl]-methanone (GSK484), an inhibitor of PAD4, was delivered via intraperitoneal injection to inhibit PAD4 activity. Cardiac PAD4 expression, tissue injury scoring, neutrophil infiltration, cit-H3 expression, NET formation, inflammatory cytokine secretion, apoptosis, and cardiac function were analyzed. In the current study, we discovered the protective effect of PAD4 inhibition using the PAD4-specific inhibitor GSK484 in cardiomyocytes challenged by MI. GSK484-mediated PAD4 inhibition can moderately preserve ventricle histological structure and myocardium integrity after MI, thereby reducing the infarct size and decreasing myocardial enzyme levels in serum. PAD4 inhibition also effectively protects cardiomyocytes from MI-induced NET formation and inflammatory cytokine secretion, in turn alleviating cardiac ischemia-induced apoptosis of cardiomyocytes. Collectively, these findings demonstrate the efficacy of specific PAD4 inhibition in reducing MI-induced neutrophil infiltration, NET formation, inflammatory reaction, and cardiomyocyte apoptosis, thereby increasing overall cardiac function improvement. These results provide novel insights for the development of new strategies to treat cardiovascular dysfunction in MI patients.

Cadherin-11 blockade reduces inflammation-driven fibrotic remodeling and improves outcomes after myocardial infarction

Over one million Americans experience myocardial infarction (MI) annually, and the resulting scar and subsequent cardiac fibrosis gives rise to heart failure. A specialized cell-cell adhesion protein, cadherin-11 (CDH11), contributes to inflammation and fibrosis in rheumatoid arthritis, pulmonary fibrosis, and aortic valve calcification but has not been studied in myocardium after MI. MI was induced by ligation of the left anterior descending artery in mice with either heterozygous or homozygous knockout of CDH11, wild-type mice receiving bone marrow transplants from Cdh11-deficient animals, and wild-type mice treated with a functional blocking antibody against CDH11 (SYN0012). Flow cytometry revealed significant CDH11 expression in noncardiomyocyte cells after MI. Animals given SYN0012 had improved cardiac function, as measured by echocardiogram, reduced tissue remodeling, and altered transcription of inflammatory and proangiogenic genes. Targeting CDH11 reduced bone marrow-derived myeloid cells and increased proangiogenic cells in the heart 3 days after MI. Cardiac fibroblast and macrophage interactions increased IL-6 secretion in vitro. Our findings suggest that CDH11-expressing cells contribute to inflammation-driven fibrotic remodeling after MI and that targeting CDH11 with a blocking antibody improves outcomes by altering recruitment of bone marrow-derived cells, limiting the macrophage-induced expression of IL-6 by fibroblasts and promoting vascularization.

Podoplanin neutralization improves cardiac remodeling and function after acute myocardial infarction

Podoplanin, a small mucine-type transmembrane glycoprotein, has been recently shown to be expressed by lymphangiogenic, fibrogenic and mesenchymal progenitor cells in the acutely and chronically infarcted myocardium. Podoplanin binds to CLEC-2, a C-type lectin-like receptor 2 highly expressed by CD11bhigh cells following inflammatory stimuli. Why podoplanin expression appears only after organ injury is currently unknown. Here, we characterize the role of podoplanin in different stages of myocardial repair after infarction and propose a podoplanin-mediated mechanism in the resolution of post-MI inflammatory response and cardiac repair. Neutralization of podoplanin led to significant improvements in the left ventricular functions and scar composition in animals treated with podoplanin neutralizing antibody. The inhibition of the interaction between podoplanin and CLEC-2 expressing immune cells in the heart enhances the cardiac performance, regeneration and angiogenesis post MI. Our data indicates that modulating the interaction between podoplanin positive cells with the immune cells after myocardial infarction positively affects immune cell recruitment and may represent a novel therapeutic target to augment post-MI cardiac repair, regeneration and function.

Impact of inflammation-mediated response on pan-coronary plaque vulnerability, myocardial viability and ventricular remodeling in the postinfarction period - the VIABILITY study: Protocol for a non-randomized prospective clinical study

INTRODUCTION

While the role of inflammation in acute coronary events is well established, the impact of inflammatory-mediated vulnerability of coronary plaques from the entire coronary tree, on the extension of ventricular remodeling and scaring, has not been clarified yet.

MATERIALS AND METHODS

The present manuscript describes the procedures of the VIABILITY trial, a descriptive prospective single-center cohort study. The main purpose of this trial is to assess the link between systemic inflammation, pan-coronary plaque vulnerability (referring to the plaque vulnerability within the entire coronary tree), myocardial viability and ventricular remodeling in patients who had suffered a recent ST-segment elevation acute myocardial infarction (STEMI). One hundred patients with STEMI who underwent successful revascularization of the culprit lesion in the first 12 hours after the onset of symptoms will be enrolled in the study. The level of systemic inflammation will be evaluated based on the serum biomarker levels (hs-CRP, matrix metalloproteinases, interleukin-6) in the acute phase of the myocardial infarction (MI) and at 1 month. Pan-coronary plaque vulnerability will be assessed based on serum biomarkers known to be associated with increased plaque vulnerability (V-CAM or I-CAM) and at 1 month after infarction, based on computed tomographic angiography analysis of vulnerability features of all coronary plaques. Myocardial viability and remodeling will be assessed based on 3D speckle tracking echocardiography associated with dobutamine infusion and LGE-CMR associated with post-processing imaging methods. The study population will be categorized in 2 subgroups: subgroup 1 - subjects with STEMI and increased inflammatory response at 7 days after the acute event (hs-CRP ≥ 3 mg/dl), and subgroup 2 - subjects with STEMI and no increased inflammatory response at 7 days (hs-CRP < 3 mg/dl). Study outcomes will consist in the rate of post-infarction heart failure development and the major adverse events (MACE) rate.

CONCLUSION

VIABILITY is the first prospective study designed to evaluate the influence of infarct-related inflammatory response on several major determinants of post-infarction outcomes, such as coronary plaque vulnerability, myocardial viability, and ventricular remodeling.

Experimental myocardial infarction induces altered regulatory T cell hemostasis, and adoptive transfer attenuates subsequent remodeling

Background

Ischemic cardiac damage is associated with upregulation of cardiac pro-inflammatory cytokines, as well as invasion of lymphocytes into the heart. Regulatory T cells (Tregs) are known to exert a suppressive effect on several immune cell types. We sought to determine whether the Treg pool is influenced by myocardial damage and whether Tregs transfer and deletion affect cardiac remodeling.

Methods and Results

The number and functional suppressive activity of Tregs were assayed in mice subjected to experimental myocardial infarction. The numbers of splenocyte-derived Tregs in the ischemic mice were significantly higher after the injury than in the controls, and their suppressive properties were significantly compromised. Compared with PBS, adoptive Treg transfer to mice with experimental infarction reduced infarct size and improved LV remodeling and functional performance by echocardiography. Treg deletion with blocking anti-CD25 antibodies did not influence infarct size or echocardiographic features of cardiac remodeling.

Conclusion

Treg numbers are increased whereas their function is compromised in mice with that underwent experimental infarction. Transfer of exogeneous Tregs results in attenuation of myocardial remodeling whereas their ablation has no effect. Thus, Tregs may serve as interesting potential interventional targets for attenuating left ventricular remodeling.

[Immune status of patients with persistent atrial fibrillation and coronary heart disease]

We estimated the strength of immune response to chlamydial infection in patients with CHD. It was most pronounced in CHD patients with atrial fibrillation (AF). There was close relationship between past chlamydial infection and markers of inflammation (CRP and TNF-alpha). The study demonstrated high prognostic value of these markers for the development of AF during CHD and their relationship with characteristics of structural and functional remodeling of myocardium during CHD with AF. The study confirmed the role of inflammation in pathogenesis of AF in CHD patients.

[Interaction of the neurohumoral and immune mechanisms of progression of myocardial damage]

The review summarizes data on the interference of the neuroendocrine and immune mechanisms of myocardial remodeling. It shows a role of the effectors of the renin-angiotensin-aldosterone (aldosterone and angiotensin II) and sympathoadrenal (noradrenaline) systems in the activation of macrophages, the production of proinflammatory cytokines and inflammatory cell chemoattractants. It is noted that proinflammatory cytokines in turn promote the activation of these neuroendocrine systems. Natriuretic peptides exert an anti-inflammatory effect, but their production can be activated by proinflammatory cytokines.

[Prognostic significance of typical immune reactions in myocardial infarction]

AIM

To ascertain the role of typical reactions of the immune system in early prognostication of congestive cardiac failure (CCF) in patients with primary transmural anterior myocardial infarction (MI) in the postinfarction period.

MATERIAL AND METHODS

Typical immune reactions were studied for a year after the disease onset. A total of 228 males aged 40-60 years (mean age 53.8 +/- 4.1 years) with primary Q-wave MI of anterior location without accompanying diseases or allergy, with comparable volumes of myocardial necrosis were included in the trial. The control group consisted of 35 healthy men aged 40 to 60 years (mean age 52.9 +/- 4.3 years). Morphofunctional characteristics of the heart were studied by Doppler echocardiography within a month since MI onset and a year after MI. Immunological examination performed on MI day 1, 15 and 25 included determination by tests of the first-second level by R. V. Petrov of the count of leukocytes, lymphocytes, T-cells, T-helpers, T-suppressors (CD3+, CD4+, CD9+), zero lymphocytes, immunoglobulins, circulating immune complexes, complement by 50% hemodialysis, phagocyte index and count. Statistical processing included parametrical and non-parametrical criteria, correlation-regression analysis, criterion chi-square. The index of diagnostic significance Kj was calculated. Also, frequency and graphic analyses were made.

RESULTS

The analysis of immunological disorders in patients with five variants of primary Q-wave MI (LV aneurism with moderate dilatation of the cavity, aneurism of the heart in combination with L V cavity dilation with CDR >60 mm and development of mitral regurgitation >2 degrees, prevalence of LV diastolic dysfunction, progressive dilatation of the heart cavities with development of mitral of degree 2-3 and tricuspidal of degree 1-2 insufficiency, compensated hemodynamics without essential changes of the LV and LA) has established the same type of immune reactions to the pathological process manifesting with a fall in the count of absolute and relative count of lymphocytes, T-cells, T-helpers, B-lymphocytes, complement, phagocytic index, suppression index. These changes were accompanied with increased count of T-suppressors, zero-lymphocytes, CIC, immunoglobulins, leucointoxication index. The immunological examination of the patients showed that all morphofunctional variants of the myocardium correlated with suppression of immune reaction in the following order: compensated aneurism of the LV (18 parameters), diastolic dysfunction of the LV (11), progressive dilatation of the heart cavities (8), aneurism of the LV (6), marked dilatation of the heart cavities (4). Patients with pronounced dynamics of the regenerative processes had suppression of cellular immunity of the second degree, in positive hemodynamics there were characteristic changes in T-suppressor link of immunity in accumulation of zero lymphocytes. Patients with poor outcome of primary Q-MI had the same formula of immune parameters: reduced count of T-helpers, high values of T-suppressors and CIC. Thus, the data show that low count of T-helpers, common T-cells, high level of T-suppressors or zero-cells during post-MI month 1 are related with compensated regeneration of the cardiac muscle. If the patients have deviation of the regulatory index and accumulation of CIC, they have poor prognosis. Regarding the time since MI (1, 15 or 25 days), the following regulation was seen: patients with compensated hemodynamics have 4 decreased and 1 increased parameters of immune status; patients with pathological myocardial remodeling have stimulation of at least 5-6 parameters of the immune status.

CONCLUSION

Myocardial remodeling of the LV proceeds within the first year after development of myocardial necrosis; outcomes of myocardial restoration correlate with severity of immune disorders forming 2-3 weeks after MI, suppression of cell reactions agrees with compensated hemodynamics; accumulation of CIC in blood points to the risk of pathological remodeling of the left ventricle and post-MI cardiac failure.

Macrophage depletion impairs wound healing and increases left ventricular remodeling after myocardial injury in mice

Macrophages have been suggested to be beneficial for myocardial wound healing. We investigated the role of macrophages in myocardial wound healing by inhibition of macrophage infiltration after myocardial injury. We used a murine cryoinjury model to induce left ventricular damage. Infiltrating macrophages were depleted during the 1st week after cryoinjury by serial intravenous injections of clodronate-containing liposomes. After injury, the presence of macrophages, which secreted high levels of transforming growth factor-beta and vascular endothelial growth factor-A, led to rapid removal of cell debris and replacement by granulation tissue containing inflammatory cells and blood vessels, followed by myofibroblast infiltration and collagen deposition. In macrophage-depleted hearts, nonresorbed cell debris was still observed 4 weeks after injury. Secretion of transforming growth factor-beta and vascular endothelial growth factor-A as well as neovascularization, myofibroblast infiltration, and collagen deposition decreased. Moreover, macrophage depletion resulted in a high mortality rate accompanied by increased left ventricular dilatation and wall thinning. In conclusion, infiltrating macrophage depletion markedly impairs wound healing and increases remodeling and mortality after myocardial injury, identifying the macrophage as a key player in myocardial wound healing. Based on these findings, we propose that increasing macrophage numbers early after myocardial infarction could be a clinically relevant option to promote myocardial wound healing and subsequently to reduce remodeling and heart failure.

Impact of serum C-reactive protein elevation on the left ventricular spherical change and the development of mitral regurgitation after anterior acute myocardial infarction

BACKGROUND/AIMS

Mitral regurgitation (MR) is frequently observed in patients with acute myocardial infarction (AMI), and is known to convey an adverse prognosis. We sought to clarify the relationship between MR and left ventricular (LV) remodeling, in association with serum C-reactive protein (CRP) elevation.

METHODS/RESULTS

A total of 181 patients with first anterior ST-elevation AMI were examined. MR was detected in 68 patients by color Doppler echocardiography 2 weeks after AMI, and the patients with MR were associated with higher incidence of readmission for heart failure. Serum CRP was serially measured, and the peak serum CRP level was markedly increased in patients with MR compared with those without MR. Multiple logistic regression analysis showed that peak CRP tertile was an independent determinant of MR after AMI (p < 0.0001). In the substudy, the increases in LV end-diastolic volume and sphericity index were higher in patients with MR than in those without MR.

CONCLUSIONS

MR during the early phase of anterior AMI was associated with LV spherical change and late-phase heart failure, in association with increased serum CRP level. These findings suggest an important role of the inflammatory response in the development of ischemic MR and LV remodeling.

Increased expression of syndecan-1 protects against cardiac dilatation and dysfunction after myocardial infarction

BACKGROUND

The cell-associated proteoglycan syndecan-1 (Synd1) closely regulates inflammation and cell-matrix interactions during wound healing and tumorigenesis. The present study investigated whether Synd1 may also regulate cardiac inflammation, matrix remodeling, and function after myocardial infarction (MI).

METHODS AND RESULTS

First, we showed increased protein and mRNA expression of Synd1 from 24 hours on, reaching its maximum at 7 days after MI and declining thereafter. Targeted deletion of Synd1 resulted in increased inflammation and accelerated, yet functionally adverse, infarct healing after MI. In concordance, adenoviral gene expression of Synd1 protected against exaggerated inflammation after MI, mainly by reducing transendothelial adhesion and migration of leukocytes, as shown in vitro. Increased inflammation in the absence of Synd1 resulted in increased monocyte chemoattractant protein-1 expression, increased activity of matrix metalloproteinase-2 and -9, and decreased activity of tissue transglutaminase, associated with increased collagen fragmentation and disorganization. Exaggerated inflammation and adverse matrix remodeling in the absence of Synd1 increased cardiac dilatation and impaired systolic function, whereas gene overexpression of Synd1 reduced inflammation and protected against cardiac dilatation and failure.

CONCLUSIONS

Increased expression of Synd1 in the infarct protects against exaggerated inflammation and adverse infarct healing, thereby reducing cardiac dilatation and dysfunction after MI in mice.

Interleukin-10 is not a critical regulator of infarct healing and left ventricular remodeling

OBJECTIVE

Interleukin-10 (IL-10) exerts potent anti-inflammatory actions and modulates matrix metalloproteinase expression. We hypothesized that endogenous IL-10 may regulate infarct healing and left ventricular remodeling by promoting resolution of the post-infarction inflammatory response and by modulating extracellular matrix metabolism.

METHODS

IL-10 null and wildtype (WT) mice underwent reperfused infarction protocols. We compared the healing response and remodeling-associated parameters between IL-10-/-and WT infarcts. In addition, we studied the effects of IL-10 on inflammatory gene synthesis by stimulated murine cardiac fibroblasts.

RESULTS

Infarcted IL-10-/-mice exhibited comparable mortality rates with WT animals. Although IL-10-/-mice had higher peak tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein (MCP)-1/CCL2 mRNA levels in the infarcted heart than WT mice, both groups demonstrated timely repression of pro-inflammatory cytokine and chemokine mRNA synthesis after 24 h of reperfusion and exhibited a similar time course of resolution of the neutrophil infiltrate. IL-10 gene disruption did not alter fibrous tissue deposition and dilative remodeling of the infarcted heart. Pre-incubation with IL-10 did not modulate the pro-inflammatory phenotype of TNF-alpha-stimulated cardiac fibroblasts, failing to inhibit chemokine mRNA synthesis. In contrast, transforming growth factor (TGF)-beta1 pre-incubation suppressed interferon-gamma-inducible protein (IP)-10/CXCL10 synthesis by cardiac fibroblasts exposed to TNF-alpha.

CONCLUSIONS

IL-10 signaling plays a non-critical role in suppression of inflammatory mediators, resolution of the inflammatory response, and fibrous tissue deposition following myocardial infarction. This may be due to the relative selectivity of IL-10-mediated anti-inflammatory actions, with respect to cell type and stimulus. Resolution of post-infarction inflammation is likely to involve multiple overlapping regulatory mechanisms controlling various pro-inflammatory pathways activated in the infarcted myocardium.

Autoimmunity in myocardial infarction

Myocardial infarction is associated with an immune response. Physiological inflammation response causes self-repair and protection, while pathological autoimmune response leads to ventricular remodeling and heart failure. Laying emphasis on regulating the immune function may become a new target for the prevention of heart failure after myocardial infarction. This review focuses on the mechanism of immune-mediated ventricular remodeling and the immune therapy after myocardial infarction.

[Autoantibodies against alpha1 adrenergic receptor related with cardiac remodeling in hypertensive patients by clinical observation]

OBJECTIVE

To investigate the effects of autoantibodies against alpha(-) adrenergic receptor on cardiac remodeling in patients with hypertension.

METHODS

Five hundred and fifty three patients with hypertension in our hospital were selected. The autoantibodies against alpha(1) adrenergic receptor in sera of donor were detected by ELISA, and the results of echocardiography were recorded. By multiple logistic regressions, the risk factors were analyzed on left ventricular enlargement of hypertension.

RESULTS

The percentage of autoantibodies against alpha(1) adrenergic receptor positive was 32.3% (179/553). There were significant difference between the positive group and negative group on the ratio of left atrial enlargement (53.6%, 44.3%, respectively; P < 0.05) and left ventricular enlargement (12.8%, 6.1%, respectively; P < 0.01). The result of regression analysis demonstrated that 4 risk factors were related to left ventricular enlargement, including male, course of disease, heart rate (HR) and autoantibodies against alpha(1) adrenergic receptor in the serum (all P < 0.05).

CONCLUSIONS

The autoantibodies against alpha(1) adrenergic receptor have a relationship with left ventricular enlargement of hypertension. Patients with the activity of autoantibodies against alpha(1) adrenergic might contribute to predict cardiac remodeling.

Role of T lymphocytes in hypertension-induced cardiac extracellular matrix remodeling

Cardiac remodeling in response to pressure overload involves reorganization of the myocytes and extracellular matrix (ECM). Neurohormonal pathways have been described as effector pathways in left ventricular ECM reorganization in response to pressure overload; we now are assessing the role of the T lymphocyte in this process. Mice with defined differences in T-lymphocyte function (C57BL/6 SCID, C57BL/6 WT, and BALB/c) were treated with 50 mg/L of N(G)-nitro-l-arginine methyl ester in their drinking water for 30 days. The immune function of C57BL/6 WT mice was T-helper type 1 (TH1), BALB/c was TH2, and C57BL/6 SCID was null. The arterial blood pressure increased by 30% in all of the strains of mice. However, ventricular stiffness significantly decreased in the C57 SCID, significantly increased in the BALB/c, and did not change in the C57 WT. The characterization of matrix metalloproteinase induction and activation on day 30 was associated with T-lymphocyte function. The total cardiac fibrillar collagen, percentage of fibrillar collagen cross-linking, and the activity of the cross-linking enzyme lysyl oxidase-like-3 (LOXL-3) significantly decreased in the C57 SCID, significantly increased in the BALB/c, and did not change in the C57 WT. This study revealed that the LOXL-3 pathway, namely, gene expression, enzymatic activities, and LOXL-3-mediated collagen cross-linking, was associated with ventricular stiffness and incongruence with lymphocyte function. These data support the concept that the T lymphocytes may play a fundamental regulatory role in cardiac ECM composition through modulation of collagen synthesis, degradation, and cross-linking.

ANG II-induced cardiac molecular and cellular events: role of aldosterone

Chronic elevation of circulating ANG II is associated with cardiac remodeling in patients with hypertension and heart failure. The underlying mechanisms, however, are not completely defined. Herein, we studied ANG II-induced molecular and cellular events in the rat heart as well as their links to the redox state. We also addressed the potential contribution of aldosterone (ALDO) on ANG II-induced cardiac remodeling. In ANG II-treated rats, and compared with controls, we found: 1) the expression of proinflammatory/profibrogenic mediators was significantly increased in the perivascular space and at the sites of microscopic injury in both ventricles; 2) macrophages and myofibroblasts were primary repairing cells at these sites, together with increased fibrillar collagen volume; 3) apoptotic macrophages and myofibroblasts were evident at the same sites; 4) NADPH oxidase (gp91phox) was significantly enhanced at these regions and primarily expressed by macrophages, whereas superoxide dismutase and catalase levels remained unchanged; 5) plasma 8-isoprostane levels were significantly increased; and 6) blood pressure was significantly elevated. Losartan treatment completely prevented cardiac oxidative stress as well as molecular/cellular responses and normalized blood pressure. Spironolactone treatment partially suppressed the cardiac inflammatory/fibrogenic responses and redox state. Thus chronic elevation of circulating ANG II is accompanied by a proinflammatory/profibrogenic phenotype involving vascular and myocardial remodeling in both ventricles. Enhanced reactive oxygen species production at these sites and increased plasma 8-isoprostane indicate the involvement of oxidative stress in ANG II-induced cardiac injury. ALDO contributes, in part, to ANG II-induced cardiac molecular and cellular responses.

[Impact of chronic Chlamydia pneumoniae infection on left ventricular remodeling after myocardial infarction]

BACKGROUND

Postmyocardial infarction left ventricular remodeling is modified by inflammatory processes and structural changes in the myocardium. Chlamydia pneumoniae (Chp) causes chronic myocyte infection, affects apoptosis and TNF-alpha production, and may induce cross reactivity with alpha myosin. This is the way in which this intracellular pathogen may modulate remodeling on the cellular and organ level.

MATERIAL AND METHODS

The study was conducted in 101 patients with a first myocardial infarction in whom we evaluated the serological features of Chp infection using the ELISA method and echocardiographic left ventricular volume at 10 days and 10 weeks after the infarction.

RESULTS

Patients with chronic Chp infection had a tendency toward higher end-diastolic volume at 10 weeks after the infarction (123 +/- 32.9 ml vs. 134 +/- 34.7 ml, p = 0.09). In order to better define this relationship we used ROC analysis and measured levels of antibodies: IgG = 117 EIU and IgA = 15.6 EIU by which we divided the patients into two subgroups. Those with IgG > or = 117 EIU and IgA > or = 15.6 EIU belong to the subgroup with chronic and active Chp infection. These patients had larger left ventricular end-diastolic volumes (155.8 vs. 123.1 ml, p = 0.0005) and end-systolic volumes (77.4 vs. 59.5 ml, p = 0.006) at 10 weeks after the infarction. Both subgroups were similar with respect to age, gender, history of arterial hypertension, systolic and diastolic blood pressure values, infarct site, reperfusion, infarct size, left ventricular ejection fraction and left ventricular contractility index. Type of reperfusion therapy and pharmacological treatment at 10 days and at 10 weeks did not differ, either.

CONCLUSIONS

Chronic Chlamydia pneumonie infection modifies the course of left ventricular remodeling.

[Immune mechanism of cardiac remodeling induced by antibodies against to the alpha1-adrenergic receptor]

OBJECTIVE

To study the effects of autoantibodies against alpha1-adrenergic receptor on the cardiac remodeling and relevant mechanism.

METHODS

Four-week-old male Wistar rats were immunized with synthesized second extracellular loop of alpha1-adrenergic receptor and raised for one year, with spontaneously hyperetensive rats (SHRs) and no-immunized Wistar rats of the same age as controls. Every one or two months blood was collected from the caudal vein to detect the level of serum antibodies to alpha1-adrenergic receptor by ELISA and the systolic blood pressure (SBP) and heart rate were measured. One year after the rats were killed and their hearts were taken out. The heart weight/body weight ratio, cardiac muscle cell cross-sectional area (CSA), interstitial collagen volume fraction (CVF) and the ratio of perivascular collagen area to vessel luminal area (PVCA) were calculated, the expression of alpha1-adrenergic receptor, c-fos and c-Jun in heart were measured by RT-PCR, Western blotting and immunohistochemistry.

RESULTS

During the experiment the blood pressure of the SHRs were significantly higher than those of the immunization group and normal control group (both P < 0.01) without significant difference between the 2 latter groups. The heart weight/body weight ratio, CSA, CVF and PVCA of the immobilization group were 3.32 mg/g +/- 0.25 mg/g, 231 microm(2) +/- 11 microm(2), 5.40% +/- 0.66% and 1.89 +/- 0.62 respectively, all significantly higher than those of the normal control group (3.06 mg/g +/- 0.25 mg/g, 197 microm(2) +/- 19 microm(2), 3.22% +/- 0.15% and 0.86 +/- 0.17 respectively), but still significantly lower than those of the SHR group. Since the second week after immunization, the titre of antibody against of the immunization group began increase, peaked in the second and third months, and then decreased slowly, and remained at a high level by the end of experiment. The titre of antibody was not correlated with blood pressure. Hypertrophy of cardiac muscle cells and increase of sedimentation of collagen in stroma were seen in the hearts of the immunization group. RT-PCR showed that the expression of alpha1D-adrenergic receptor mRNA of the immunization group was 0.55 +/- 0.01, significantly lower than that of the normal control group (0.88 +/- 0.08, P < 0.05); the expression of c-jun mRNA in the immunization group was 0.82 +/- 0.02, significantly higher than that in the normal control group (0.42 +/- 0.07, P < 0.05); and there were no significant differences in the expressions of heart alpha1A- and alpha1B-afrenergic receptors and c-fos mRNAs between these 2 groups. Western blotting showed that the expression of c-jun protein in the immunization group was 6.24 +/- 2.13, significantly higher than that in the normal control group (2.55 +/- 0.58, P < 0.05); and there were no significant differences in the expressions of c-fos andalpha1A-adrenergic receptor proteins between these 2 groups.

CONCLUSION

The antibodies against alpha1-adrenergic receptor up-regulates the expression of c-jun in cardiac muscle cells and interstitial fibroblast, which may be an immunologic mechanism of cardiac remodeling.

Relationship of myocardial remodeling to the genesis of serum autoantibodies to cardiac beta(1)-adrenoceptors and muscarinic type 2 acetylcholine receptors in rats

OBJECTIVES

We sought to investigate the mechanism responsible for the occurrence of anticardiac receptor autoantibodies.

BACKGROUND

Increasing evidence suggests the involvement of autoimmune mechanisms in the pathogenesis of a number of cardiovascular diseases. Among them, the biologic, functional and pathogenic properties of anticardiac receptor antibodies have been extensively investigated. However, the mechanism responsible for the occurrence of anticardiac receptor autoantibodies remains poorly understood.

METHODS

Two rat models (aortic banding [AB] and adriamycin [ADR] groups) were constructed. Determination of cardiac function and morphology and T-lymphocyte subtypes, enzyme-linked immunosorbent assay and cardiomyocyte cultures were performed.

RESULTS

It was shown, in the AB and ADR groups, that the frequency and titer of autoantibodies to beta(1) and muscarinic type 2 receptors were increased when myocardial remodeling occurred, as evidenced by significant cardiac morphologic changes, deposition of collagen and obvious functional impairment. This suggests that cardiac remodeling itself, in two disparate models of heart failure and cardiomyopathy, was able to trigger the genesis of anticardiac receptor autoantibodies. These autoantibodies have biologic effects similar to those seen in human autoantibodies. They have also shown a characteristic self-growth, as well as a time-course decline, suggesting that a negative finding of anticardiac receptor autoantibodies in sera of patients with heart disease does not necessarily imply that there is no autoimmune reaction involved in the pathogenesis.

CONCLUSIONS

Our results demonstrated that myocardial damage was able to trigger the occurrence of an autoimmune reaction, resulting in the genesis of anticardiac receptor autoantibodies with properties similar to those seen in patients with idiopathic dilated cardiomyopathy.

Relationship between plasma level of cardiotrophin-1 and left ventricular mass index in patients with dilated cardiomyopathy

OBJECTIVES

The study evaluated the relationship between plasma cardiotrophin-1 (CT-1) concentration and left ventricular (LV) mass in dilated cardiomyopathy (DCM) patients with congestive heart failure (CHF).

BACKGROUND

Cardiotrophin-1 is a newly identified member of the interleukin-6 (IL-6) family of cytokines and one of the endogenous ligands for gp130 signaling pathways in the heart, and it has potent hypertrophic and survival effects on cardiac myocytes. However, the clinical significance of CT-1 is poorly understood.

METHODS

We measured the plasma CT-1 level in 51 consecutive patients with DCM. Patients were classified into two groups: small LV mass index group and large LV mass index group, based on the median level of LV mass index.

RESULTS

The plasma CT-1 level was increased in DCM patients with the severity of CHF and was significantly higher in the large LV mass group than in the small LV mass group, despite the absence of a difference in LV ejection fraction between the two groups. In addition, there was a significant positive correlation between the plasma CT-1 level and the LV mass index (r = 0.627, p < 0.0001). According to stepwise multivariate analyses among hemodynamic and neurohumoral factors, a high plasma CT-1 level showed an independent and significant positive relationship with a large LV mass index in patients with DCM.

CONCLUSIONS

These results indicate that the plasma CT-1 level is increased in patients with DCM and is significantly correlated with the LV mass index, suggesting that CT-1 plays an important role in structural LV remodeling in patients with DCM.

Neutralization of interleukin-1beta in the acute phase of myocardial infarction promotes the progression of left ventricular remodeling

OBJECTIVES

We sought to examine the role of the pro-inflammatory cytokine, interleukin-1-beta (IL-1beta), in the process of left ventricular (LV) remodeling in the early phase after myocardial infarction (MI).

BACKGROUND

Studies have shown that pro-inflammatory cytokines are closely related to the progression of LV remodeling after MI.

METHODS

Mice underwent coronary artery ligation, and the time course of LV remodeling was followed up to 20 weeks. The gene expression level of IL-1beta was examined. In a second set of experiments, the mice underwent coronary artery ligation followed by treatment with anti-IL-1beta antibody (100 microg, intravenously), versus control immunoglobulin G (100 microg, intravenously) immediately after the operation.

RESULTS

Rapid hypertrophy of noninfarcted myocardium was observed by four weeks, and interstitial fibrosis progressed steadily up to 20 weeks. Anti-IL-1beta treatment increased the occurrence of ventricular rupture and suppressed collagen accumulation in the infarct-related area. At four and eight weeks after the operation, total heart weight and LV end-diastolic dimension were significantly greater in the anti-IL-1beta-treated mice than in the other groups. In the infarct-related area, collagen accumulation was suppressed, whereas in the noninfarcted area, pro-collagen gene expression levels, particularly type III, were decreased in the anti-IL-1beta-treated mice.

CONCLUSIONS

Anti-IL-1beta treatment suppressed pro-collagen gene expression and delayed wound healing mechanisms-properties that are likely to lead to progression of LV remodeling. In the acute phase of MI, IL-1beta appears to play a protective role.

Pathogenesis of heart failure

Heart failure is a complex clinical syndrome, and only part of this syndrome is based on the mechanical failure of the heart muscle itself to provide sufficient systemic perfusion. Heart failure is accompanied by the activation of various immunologic and neurohumoral mechanisms. These may be intended by nature to be physiologically beneficial, but eventually become deleterious as they provoke ischemic, proarrhythmic, vascular, and structural changes in the myocardium that contribute to the versatile symptoms of the heart failure syndrome. Today's concept of the pathogenesis of heart failure regards heart failure as a dynamic state influenced by at least 2 major mechanisms, namely "neurohumoral" activation and ventricular remodeling. Progressive chronic heart failure can be viewed as a result of the prolonged impact of both pathogenetic mechanisms. This article will describe briefly the features of the neurohumoral forces on the pathogenesis of heart failure, including immunologic forces, which also influence the remodeling process.